1. Field of the Invention
The present invention relates to a method of fabricating a thin film device, and more particularly, to a method of fabricating a thin film device using a thin film transcription process that can be used as a technology of fabricating a flexible device.
2. Description of the Related Art
In general, thin film transcription technology has been widely used in a thin film transistor (TFT), an electronic device and an optical device such as an organic electroluminescent (EL) device.
The thin film transcription technology refers to a technology of fabricating a desired thin film device by transcribing a necessary thin film formed in the preliminary substrate to a permanent substrate. This thin film transcription technology can be efficiently used when the condition of a substrate used to form a film is different from the condition of a substrate used for a thin film device.
For example, the thin film transcription technology can be beneficially used when a substrate used for a device has a low heat-resisting property or low softening point and melting points even though a relatively high temperature process is required in a semiconductor film formation technology. Specifically, the thin film transcription technology can also be beneficially used in a flexible thin film device.
Since a related art flexible device requires flexibility, an organic substrate such as a polymer has been mainly used and an organic thin film has been used as a thin film forming a function unit on the surface of the organic substrate. However, because it is difficult to ensure high performance of the function unit implemented by the organic thin film, the function unit of the flexible device needs to be formed of an inorganic matter such as a poly-silicon or an oxide. In this case, because a high temperature semiconductor film formation technology is difficult to directly apply to a flexible organic substrate, the thin film transcription technology is used to transcribe a thin film formed of an inorganic matter such as a semiconductor to other preliminary substrate.
However, in the thin film transcription technology, a surface separated from a preliminary substrate is provided on the upper surface of a thin film transcribed to a permanent substrate. Also, a residue of a sacrifice layer may remain on the upper surface of the thin film. Accordingly, a removal process of the residue of the sacrifice layer is necessary to prevent a harmful effect on the thin film device.
On the other hand, a laser irradiation or a wet etching process may be used in a process of removing the sacrifice layer. In the case of the laser irradiation, a thin film device may be damaged by a laser output during the laser irradiation.
Moreover, in the case of the wet etching process, a structure of the thin film may be adhered to a substrate, and a relatively low etching selectivity may cause an inconvenience of requiring a separate photoresist process to protect a thin film device region.